cryptosystemn.

1949 Federal Reg. 21 Apr. 1931/2 Messages may be encrypted in authorized cryptosystems for other departments of the Government or for commercial firms engaged in producing war materials under Government contract.

1957 W. F. Friedman & E. S. Friedman Shakespearean Ciphers Examined ii. 26 Crypto-systems of this sort..are technically known as ‘concealment systems’... We shall only ask whether the solutions are valid: that is to say, whether the plain texts make sense, and the cryptosystem and the specific keys can be, or have been, applied without ambiguity.

1967 D. Kahn Codebreakers xiv. 404 It is self-evident that, as the number of plaintext elements increase, so does the security of a cryptosystem.

1989 W. Weaver tr. U. Eco Foucault's Pendulum cvi. 537 So he translates his fine Rosicrucian sentence using a Trithemius cryptosystem.

2005 New Scientist 6 Aug. 43/3 If new discoveries like the AKS algorithm can lurk in the wings, then we have to worry that current cryptosystems may not be quite as secure as we fondly imagine.